The range and standard deviation of the numbers In list Ware equal to /and s, respectively. What is the value of s?
At a certain used-book store, the cost of each paperback book is x dollars and the cost of each hardcover book is y dollars. What is the cost of a hardcover book at the store?
(1)
At the store, the cost of 3 paperback books and 5 hardcover books is $12.25.
(2)
At the store, the cost of 9 paperback books and 15 hardcover books is $36.75.